The present invention relates to an automatic etching unit for etching semiconductor wafers, and in particular it relates to such an etching unit having (i) an automatic wafer transfer apparatus (mechanism) capable of automatically transferring all of the wafers contained in a basket to an etching drum at a time, and (ii) an etching drum capable of allowing all the wafers contained in the drum to be etched without being removed from the drum. Furthermore, the invention relates to a method for automatically transferring all of the wafers contained in a basket to the etching drum at a time.